4 (four) is a number, a numeral and a glyph representing the number. This is a natural number, which follows 3 and is preceded by 5. It is an integer and a cardinal number, that is, a number that is used for counting. In addition, it is classified as a real number, which distinguishes it from imaginary numbers.

Representing 1, 2, and 3, in as many lines since the number indicates that it works quite well, but writing four lines is tiresome. The Brahmin Indians simplified 4 by combining their four lines in a cross that resembles our modern plus sign. The Sunga and other Indians would add a horizontal line above the figure, and Kshatrapa and Pallava changed this figure so much that the writing speed was at best a secondary concern. The Arabs did not have time for cursive fancy: four of them still had the early concept of the cross, but for the sake of efficiency they were made in one movement connecting the “western” end with the “northern” end; The “eastern” end ended with a curve. The Europeans emerged from the final curve and gradually made the figure less italic, ending with a symbol very close to the original Brahman cross.

In Mathematics

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Four is the smallest composite number whose direct divisors are 1 and 2. Four is a very combined number. The next very combined number is 6.

Four is the second square number (“square number” is an integer that can be written as the square of another integer) and the second centered triangle. (“Centralized Triangle” is the total number of points when constructing a triangle with a point in the center and all other points surrounding the center in successive triangles).

Four is the maximum number of dimensions of true delegated algebra (quaternions), from the theorem of Ferdinand George Frobenius.